1. Field of the Invention
This invention relates to a curved surface shaping apparatus utilized for the shaping of various curved surfaces, which require high accuracy, such as optical curved surfaces in lenses, mirrors, light-receiving elements, light-emitting elements, etc., and to a curved surface shaping method using the same.
2. Description of the Prior Art
Generally, when a curved surface is to be obtained, it is very difficult to shape it highly accurately if the curved surface is a spherical surface, and this is particularly so if the curved surface is a non-spherical surface.
Heretofore, the curved surface of a non-spherical lens in which correction of lens aberrations is desired has been shaped by (1) the cutting of a spherical lens by a cutter, (2) the casting into a mold in which a desired non-spherical surface is formed or (3) the deposition onto a spherical lens.
However, in the case of the method mentioned under item (1) above, unevenness corresponding to the manner in which the cutter is applied to the surface is created on the shaped surface and therefore the surface must be polished after the cutting, and this makes deviation with respect to the desired curvature unavoidable. In the case of the method mentioned under item (2) above, not only the accuracy of the curved surface itself of the mold possibly poses a problem, but also the casting and cooling of a hot material (molten glass) poses problems of distortion attributable to non-uniform cooling and the heterogeneity of the surface which is in contact with the mold. In the case of the method mentioned under item (3) above, not only is it difficult to uniformly effect the deposition onto the curved surface, but also the deposition must be effected while the coverage by masking is gradually moved in accordance with the desired curvature, and this leads to cumbersomeness of the operation and the possbility of error.
Thus, it is very difficult to shape a desired curved surface highly accurately, and particularly in the case of shaping a non-spherical surface a considerable degree of error unavoidably occurs.